This disclosure is based upon French Application No. 99/06585, filed on May 25, 1999 and International Application No. PCT/FR00/01268, filed May 11, 2000, which was published on Nov. 30, 2000 in a language other than English, the contents of which are incorporated herein by reference.
The present invention relates to the manufacture of a portable electronic device including at least one integrated-circuit chip embedded in a support and electrically connected to interface elements consisting of a connection terminal block and/or an antenna.
These portable electronic devices constitute for example smart cards with and/or without contacts or electronic labels.
Smart cards with and/or without contacts are intended for performing various operations such as, for example, banking operations, telephone communications, various identification operations, or operations of the cash dispensing type.
Contact cards have metallisations flush with the surface of the card, disposed at a precise point on the card body, defined by the usual standard ISO 7816. These metallisations are intended to come into contact with a reading head of a reader with a view to an electrical transmission of data.
Contactless cards have an antenna for exchanging information with the outside by means of an electromagnetic coupling between the electronics of the card and a receiving appliance or reader. This coupling can be effected in read mode or in read/write mode, and the data transmission takes place by radio frequency or microwave.
There are also hybrid cards or xe2x80x9ccombicardsxe2x80x9d which have both metallisations flush with the surface of the card and an antenna embedded in the body of the card. This type of card can therefore exchange data with the outside either in contact mode or without contact.
As currently produced, the cards, with or without contact, are thin portable elements of standard dimensions. The standard ISO 7810 corresponds to a card with a standard format 85 mm long, 54 mm wide and 0.76 mm thick.
The majority of smart card manufacturing processes are based on the assembly of the integrated-circuit chip in a subassembly referred to as a micromodule which is connected to a communication interface and inset, that is to say placed in a cavity provided in a card body, using techniques known to experts.
A conventional manufacturing method is illustrated in FIG. 1. Such a method consists in gluing an integrated-circuit chip 10, disposing its active face with its contact pads 11 upwards, and gluing its opposite face to a dielectric support sheet 15. The dielectric sheet 15 is itself disposed on a contact grid 18 such as a metallic plate made from nickel- and gold-plated copper for example. Connection wells 16 are formed in the dielectric sheet 15 in order to enable connection wires 17 to connect the contact pads 11 on the chip 10 to the contact areas on the grid 18.
According to some variants, it is possible to glue the chip 10, active face upwards, directly on the contact grid 18, and then to connect it by hard wiring 17.
In such a variant, the grid 18 is deposited on a dielectric support 15 and the contact connection areas on the said grid are defined by chemical etching or any other known means.
A protection or encapsulation step then protects the chip 10 and the soldered connection wires 17. Use is generally made of a technique known as xe2x80x9cglob topxe2x80x9d in English terminology, which designates the coating of the chip from above. This technique consists in pouring a drop of resin 20, based on epoxy for example, thermosetting or cross-linking under ultraviolet, on the chip 10 and its connection wires 17.
FIG. 2 illustrates a variant embodiment in which the chip 10 is connected to the metallic grid 18 according to a xe2x80x9cflip chipsxe2x80x9d method, which designates a known technique in which the chip is turned over.
In the example illustrated, the chip 10 is connected to the metallic grid 18 by means of a glue 350 with anisotropic electrical conduction which is well known and often used for mounting passive components on a surface. The output pads 11 on the chip 10 are placed opposite the connection areas on the grid 18. This glue 350 in fact contains elastically deformable conductive particles which make it possible to establish electrical conduction along the z axis (that is to say along the thickness) when they are pressed between the output pads 11 and the connection areas on the grid 18, whilst providing insulation in the other directions (x,y).
In a variant embodiment, the electrical connection between the chip 10 and the grid 18 can be improved by protrusions 12, made from hot-melt alloy of the Sn/Pb type or conductive polymer, produced on the pads 11 on the chip 10.
The dielectric support 15 with the chip 10 glued and protected by the resin 20 is cut in order to constitute a micromodule 100.
In the case of a smart card with contact, the micromodule 100 is inset in the cavity in a previously decorated card body. This insetting operation can be effected by depositing a liquid glue in the cavity of the card body before attaching the micromodule.
FIG. 3 illustrates another insetting technique. The card body 110 is produced according to a conventional method, for example by injecting plastics material into a mould. The cavity 120 is obtained either by milling the card body, or by injection at the time of the manufacture of the card body in an adapted mould.
A heat-activated adhesive film 23 is deposited by hot lamination on the dielectric film 15 preferentially before the cutting out of the micromodule 100. The latter is inset in the cavity 120 in the card body 110 and glued by reactivating the heat-activated adhesive 23 by hot pressing by means of a press 24 whose shape is adapted to that of the cavity 120.
These known technologies for manufacturing contact cards have many drawbacks.
They require in fact a large number of operations. When protection by resin is effected, it is generally necessary to mill the resin in order to adapt its shape and thickness, which constitutes a tricky and expensive operation and one which places a stress on the chip.
In particular, the standard technology uses expensive techniques and a high-quality dielectric. The dielectric used is generally made from a glass epoxy composite or Kapton.
This is because the dielectric chosen must have properties of good resistance to temperature in order to be compatible with the insetting techniques described above.
In addition, the geometric definition of the different contacts and connection areas is generally obtained by chemical etching of the metallic grid deposited uniformly on the insulating support. However, chemical etching is an expensive operation.
In the case of a contactless smart card or an electronic label, the micromodule 100 is connected to an antenna 55, as illustrated for example in FIG. 4.
The antenna 55 is produced on an insulating support 52 consisting of PVC or PE or any other suitable material (polyvinyl chloride, polyethylene).
The antenna 55 is produced from a conductive material, in a coil, by screen printing with conductive ink, or by chemical etching of a metal deposited on an insulating support. It can have the shape of a spiral or any other pattern according to the required applications.
The chip 10 is glued and connected to connection areas on a metallic grid 18 by hard wiring 17 or according to any other known method, such as xe2x80x9cflip chipxe2x80x9d for example.
The chip 10 and its connection wires 16 are then protected by a resin 20 deposited according to the xe2x80x9cglob topxe2x80x9d technique described above, for example.
The connection between the antenna 55 and the metallic grid 18 can be effected by tin/lead soldering or by conductive gluing or lamination.
The body of the contactless card is then produced by hot lamination of plastic films in order to have the final thickness or by lining a resin between the two dielectric sheets 15 and 52 separated by a strut.
In the case of an electronic label, the antenna, in its definitive form, is chosen by moulding the body of the label around the electronics or by laminating plastic films or by inserting a plastic casing.
These known technologies for manufacturing contactless electronic devices have many drawbacks.
The disadvantages cited above for contactless cards are found again in the method of manufacturing contactless devices.
In addition, protecting the chip is tricky since effecting encapsulation is often impossible given the density of the module on the strip 52, which obliges the manufacturer to effect an overmoulding of the micromodule.
The aim of the present invention is to mitigate the drawbacks of the prior art.
To this end, the present invention proposes a method for manufacturing an electronic device making it possible to use inexpensive materials and in particular a less expensive dielectric.
In addition, the invention simplifies the step of connecting the chip by producing a metallic grid which is arched so as to place the pads on the chip opposite the connection areas on the grid.
The object of the present invention is more particularly a method for manufacturing an integrated-circuit electronic device, an integrated-circuit chip being attached to a dielectric support and connected to a metallic grid having contact areas and connection areas, characterised in that it includes a step consisting of producing a chip housing on a metallic grid by arching of the latter, the said housing having dimensions making it possible to receive the thickness of the chip and its contact pads, and in that the said grid is laminated on the dielectric support so as to place each contact pad on the chip opposite and in connection with the said connection areas on the grid.
According to one characteristic of the invention, the dielectric support consists of a strip leaving the contact areas on the metallic grid free.
According to another characteristic of the invention, the metallic grid also has a second arch able to encase the thickness of the dielectric strip so as to place the latter flush with the contact areas on the metallic grid.
In a variant embodiment, the dielectric strip consists of a polyethylene terephthalate (PET).
In another variant embodiment, the dielectric strip consists of an acrylonitrile butadiene-styrene (ABS).
In another variant embodiment, the dielectric strip consists of paper.
In another variant, the dielectric strip (60) consists of a polyvinyl chloride (PVC).
According to one characteristic, the dielectric strip has an adhesive surface able to provide the gluing of the chip on the said strip.
According to one characteristic, reference holes and/or targets are produced on the dielectric strip so as to effect a precise gluing of the chip on the said strip.
According to a variant embodiment, the connection of the contact pads on the chip to the connection areas on the grille is effected by laser welding.
According to another variant embodiment, protrusions made from conductive polymer material are deposited on the contact pads on the chip, the connection of the said contact pads to the connection areas on the grille being effected by hot lamination.
According to a first application of the invention, the method includes a step of attaching the micromodule in the cavity of a card body.
The attaching of a micromodule is effected by activation of an adhesive film previously laminated over the entire surface of the metallic grid.
This adhesive film also constitutes an insulant providing the protection of the chip.
According to a second application of the invention, the method includes a step of connecting the micromodule to an antenna.
The chip is then protected by lamination of an insulating film over the entire surface of the metallic grid.
Advantageously, the insulation of the central turns of the antenna is provided by the dielectric strip.
The present invention also relates to an integrated-circuit electronic module, an integrated-circuit chip being attached to a dielectric support and connected to a communication interface having contact areas and connection areas, characterised in that the communication interface consists of an arched metallic grid, the arch defining a chip housing having dimensions making it possible to receive the thickness of the chip and its contact pads, and in that the connection areas on the grid are situated opposite and in connection with the contact pads on the chip.
According to one characteristic, the dielectric support consists of a strip leaving the contact areas free.
According to another characteristic, the metallic grid has two distinct arches, a first arch encasing the thickness of the chip and its contact pads, and a second arch encasing the thickness of the dielectric strip.
According to one characteristic, a protective film is laminated over the entire surface of the metallic grid.
The present invention applies to any portable integrated-circuit device such as smart cards or electronic labels, comprising an electronic module according to the invention.
The present invention makes it possible to obtain, with a simple and economical method, a thin electronic micromodule with good resistance to moisture.
In particular, the method according to the invention makes it possible to use a lower quality dielectric since the latter does not require the conventional properties of compatibility with the usual insetting techniques.
This is because, and this will emerge more precisely below, the dielectric does not cover the contact areas of the metallic grid. However, during insetting, it is these areas which are pressed or glued with a glue of the cyanoacrylate type.
The method according to the invention has the advantage of being able to be implemented in line without interruption.
In addition, the manufacturing method according to the invention has the advantage of considerably simplifying the connection of the chips to the connection areas on the grid.
In addition, the encapsulation and milling steps are completely eliminated, since the chip is protected by the grid and a film laminated over the entire surface of the grid.